Expandable orthopedic implant

Abstract

An expandable orthopedic implant includes a casing pipe, a shaft, a first expandable element and a first link lever. The casing pipe has a first opening, a second opening and an axis passing through the first and second opening. The casing pipe sheathes one end of the shaft, and the other end of the shaft has a top portion disposed out of the first opening. The first expandable element has a first terminal pivoted on the casing pipe and a second terminal. The first link lever has a proximal end pivoted to the top portion and a distal end pivoted to the second terminal. When the top portion is driven moving away from the first opening along an extending direction of the axis, the first link-lever can be pushed by the shaft to enact the second terminal moving away from the axis along a direction perpendicular to the axis.

What is claimed is: 
     
         1 . An expandable orthopedic implant, comprising:
 a casing pipe, having a first opening, a second opening and an axis passing through the first opening and the second opening;   a shaft, wherein the casing pipe sheathes one end of the shaft, and the other end of the shaft has a head portion disposed out of the first opening;   a first expandable element, having a first terminal pivoted on the casing pipe and a second terminal; and   a first link-lever, having a first proximal end pivoted to the head portion and a first distal end pivoted to the second terminal;   when the head portion is driven moving away from the first opening along an extending direction of the axis, the first link-lever is pushed by the shaft to enact the second terminal moving away from the axis along a first direction perpendicular to the axis.   
     
     
         2 . The expandable orthopedic implant according to  claim 1 , wherein the shaft and the first link-lever from an angle ranging from 175° to 90°. 
     
     
         3 . The expandable orthopedic implant according to  claim 1 , wherein the first terminal is pivoted on the casing pipe through a first pivot bolt; and the first expandable element has a first lever arm perpendicular to the first pivot bolt and forming an angle ranging from 0° to 70° with the axis of the casing pipe. 
     
     
         4 . The expandable orthopedic implant according to  claim 3 , wherein the first link-lever is pivoted to the head portion through a second pivot bolt and has a second lever arm perpendicular to the second pivot bolt; and the first distal end and the second terminal are pivoted with each other at an intersectional point of the first lever arm and the second lever arm. 
     
     
         5 . The expandable orthopedic implant according to  claim 1 , wherein the first expandable element has an element body and a first curved part connecting with each other; the first terminal is disposed on the element body that has the first lever arm, and pivoted to the casing pipe by a first pivot bolt perpendicular to the first lever arm; and the second terminal is disposed on the first curved part and departs away from the first lever arm. 
     
     
         6 . The expandable orthopedic implant according to  claim 1 , wherein the first link-lever has a lever body and a second curved part connecting with each other; the first proximal end is disposed on the lever body that has a second lever arm, and pivoted with the head portion by a second pivot bolt perpendicular to the second lever arm; the first distal end is disposed on the second curved part and departs away from the second lever arm. 
     
     
         7 . The expandable orthopedic implant according to  claim 1 , wherein the casing pipe comprises a plurality of through-holes disposed in at least one sidewall used to define the first opening and the second opening. 
     
     
         8 . The expandable orthopedic implant according to  claim 1 , wherein the first expandable element is configured as an arc-shaped plate structure parallel to at least one sidewall of the casing pipe used to define the first opening and the second opening. 
     
     
         9 . The expandable orthopedic implant according to  claim 8 , wherein the first expandable element comprises a first spiral protrusion portion protruding from an outer edge of the first expandable element departing away the axis. 
     
     
         10 . The expandable orthopedic implant according to  claim 9 , wherein the casing pipe comprises a second spiral protrusion portion protruding from an outer edge of the at least one sidewall and surrounding the axis. 
     
     
         11 . The expandable orthopedic implant according to  claim 1 , further comprising:
 a third spiral protrusion portion protruding from an inner edge of at least one sidewall of the casing pipe used to define the first opening and the second opening; and   a first spiral guide groove concaved on a surface of the shaft and slidably engaged with the third spiral protrusion.   
     
     
         12 . The expandable orthopedic implant according to  claim 1 , further comprising:
 a second spiral guide groove concaved on an inner edge of at least one sidewall of the casing pipe used to define the first opening and the second opening; and   
       a fourth spiral protrusion portion protruding from a surface of the shaft and slidably engaged with the second spiral guide groove. 
     
     
         13 . The expandable orthopedic implant according to  claim 1 , wherein the shaft is a hollow tubular structure having a long through-hole passing through the head portion. 
     
     
         14 . The expandable orthopedic implant according to  claim 1 , wherein
 the casing pipe is divided into a first portion and a second portion connecting to the first portion; the first portion has a first internal diameter substantially equal to a diameter of the first opening; the second portion has a second internal diameter substantially greater than the diameter of the first opening; and   the shaft is divided into a third portion and a fourth portion connecting to the third portion; the third portion has a first diameter substantially less than the first internal diameter; the fourth portion has a second diameter substantially greater than the first internal diameter and less than the second internal diameter.   
     
     
         15 . The expandable orthopedic implant according to  claim 14 , wherein the casing pipe has a wedge protruding from a first connection location at which the second portion connects to the first portion; and the shaft has a flange protruding from a second connection location at which the third portion connects to the fourth portion. 
     
     
         16 . The expandable orthopedic implant according to  claim 1 , further comprising a bottom rotation resistant design inserted in the casing pipe and contacting to a tail portion of the shaft. 
     
     
         17 . The expandable orthopedic implant according to  claim 1 , further comprising:
 a second expandable element having a third terminal and a fourth terminal, wherein the third terminal is pivoted to the casing pipe; and   a second link-lever having a second proximal end pivoted to the head portion and a second distal end pivoted to the fourth terminal;   when the head portion is driven moving away from the first opening, the second link-lever is pushed by the shaft to enact the fourth terminal moving away from the axis along a second direction perpendicular to the axis.   
     
     
         18 . The expandable orthopedic implant according to  claim 17 , wherein the first direction and the second direction form a straight angle or a non-straight angle. 
     
     
         19 . The expandable orthopedic implant according to  claim 17 , further comprising:
 a third expandable element having a fifth terminal and a sixth terminal, wherein the fifth terminal is pivoted to the casing pipe; and   a third link-lever having a third proximal end pivoted to the head portion and a third distal end pivoted to the sixth terminal;   when the head portion is driven moving away from the first opening, the third link-lever is pushed by the shaft to enact the sixth terminal moving away from the axis along a third direction perpendicular to the axis.   
     
     
         20 . The expandable orthopedic implant according to  claim 18 , wherein the first direction and the second direction form a first angle; the second direction and the third direction form a second angle; and the first angle is equal to or greater than the second angle.